Quantitative classification of WR nuclei of planetary nebulae

Acker, A.; Neiner, C.

doi:10.1051/0004-6361:20030391

Cited by 124 publications

(230 citation statements)

References 37 publications

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“…This is much more than the scale height of the thin disk and therefore an unlikely location for a massive star. The central star of PB 8 has been classified as spectral type [WC5-6] by Acker & Neiner (2003). Yet we showed above that the central star of PB 8 is not a member of the [WC] sequence; its spectrum shows strong lines of nitrogen, reflecting that its chemical composition rather resembles that of a WN star.…”

Section: Pn and Central Star Statusmentioning

confidence: 74%

The central star of the planetary nebula PB 8: a Wolf-Rayet-type wind of an unusual WN/WC chemical composition

Todt

Peña

Hamann

et al. 2010

A&A

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A considerable fraction of the central stars of planetary nebulae (CSPNe) are hydrogen-deficient. As a rule, these CSPNe exhibit a chemical composition of helium, carbon, and oxygen with the majority showing Wolf-Rayet-like emission line spectra. These stars are classified as CSPNe of a spectral type [WC]. We perform a spectral analysis of CSPN PB 8 with the Potsdam Wolf-Rayet (PoWR) models for expanding atmospheres. The source PB 8 displays wind-broadened emission lines from strong mass loss. Most strikingly, we find that its surface composition is hydrogen-deficient, but not carbon-rich. With mass fractions of 55% helium, 40% hydrogen, 1.3% carbon, 2% nitrogen, and 1.3% oxygen, it differs greatly from the 30-50% of carbon which are typically seen in [WC]-type central stars. The atmospheric mixture in PB 8 has an analogy in the WN/WC transition type among the massive Wolf-Rayet stars. Therefore we suggest to introduce a new spectral type [WN/WC] for CSPNe, with PB 8 as its first member. The central star of PB 8 has a relatively low temperature of T * = 52 kK, as expected for central stars in their early evolutionary stages. Its surrounding nebula is less than 3000 years old, i.e. relatively young. Existing calculations for the post-AGB evolution can produce hydrogen-deficient stars of the [WC] type, but do not predict the composition found in PB 8. We discuss various scenarios that might explain the origin of this unique object.

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Section: Pn and Central Star Statusmentioning

confidence: 74%

The central star of the planetary nebula PB 8: a Wolf-Rayet-type wind of an unusual WN/WC chemical composition

Todt

Peña

Hamann

et al. 2010

A&A

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“…The depth achieved in MNC1-3 is adequate to detect only the brightest emission lines and their spectra offer little more than confirmation of the ESO WFI imaging. In the case of star (Acker & Neiner 2003). A more precise classification cannot however be reached until deeper spectroscopy is obtained that reaches the continuum level.…”

Section: Wifes Spectroscopymentioning

confidence: 99%

Improved prospects for the detection of new Large Magellanic Cloud planetary nebulae

Miszalski

Napiwotzki

Cioni

et al. 2011

A&A

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The Large Magellanic Cloud (LMC) contains the nearest large extragalactic population of planetary nebulae (PNe). A shallow viewing angle and low interstellar reddening towards the LMC potentially means a larger, more complete flux-limited population can be assembled than for any other galaxy. These advantages appear to be reflected by the small gap between the catalogued (∼700 PNe) and estimated (1000 ± 250 PNe) population size. With more detailed multi-wavelength studies the catalogued number of LMC PNe may fall, potentially widening this gap. We demonstrate here that the gap can be further bridged with improved optical and nearinfrared imaging surveys. We present three

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“…The CS PB 8 was classified as by Acker & Neiner (2003) based on a lowresolution spectrum. A spectral analysis based on a high resolution spectrum, Todt et al (2010) revealed that this object has a stellar temperature of about 50 kK and an unusual composition with He:H:C:N:O=55:40:1:1:1 by mass and resembles spectroscopically a massive WN/C star.…”

Section: Pbmentioning

confidence: 99%

[WN] central stars of planetary nebulae

Todt¹,

Miszalski

Toalá

et al. 2016

Proc. IAU

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Abstract. While most of the low-mass stars stay hydrogen-rich on their surface throughout their evolution, a considerable fraction of white dwarfs as well as central stars of planetary nebulae have a hydrogen-deficient surface composition. The majority of these H-deficient central stars exhibit spectra very similar to massive Wolf-Rayet stars of the carbon sequence, i.e. with broad emission lines of carbon, helium, and oxygen. In analogy to the massive Wolf-Rayet stars, they are classified as [WC] stars. Their formation, which is relatively well understood, is thought to be the result of a (very) late thermal pulse of the helium burning shell.It is therefore surprising that some H-deficient central stars which have been found recently, e.g. IC 4663 and Abell 48, exhibit spectra that resemble those of the massive Wolf-Rayet stars of the nitrogen sequence, i.e. with strong emission lines of nitrogen instead of carbon. This new type of central stars is therefore labelled [WN]. We present spectral analyses of these objects and discuss the status of further candidates as well as the evolutionary status and origin of the [WN] stars.

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Quantitative classification of WR nuclei of planetary nebulae

Cited by 124 publications

References 37 publications

The central star of the planetary nebula PB 8: a Wolf-Rayet-type wind of an unusual WN/WC chemical composition

The central star of the planetary nebula PB 8: a Wolf-Rayet-type wind of an unusual WN/WC chemical composition

Improved prospects for the detection of new Large Magellanic Cloud planetary nebulae

[WN] central stars of planetary nebulae

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